sgesc2(3)

NAME

SGESC2 - solve a system of linear equations A * X =

scale* RHS with a general N-by-N matrix A using the LU factor

ization with complete pivoting computed by SGETC2

SYNOPSIS

SUBROUTINE SGESC2( N, A, LDA, RHS, IPIV, JPIV, SCALE )
    INTEGER        LDA, N
    REAL           SCALE
    INTEGER        IPIV( * ), JPIV( * )
    REAL           A( LDA, * ), RHS( * )

PURPOSE

SGESC2 solves a system of linear equations A * X = scale*

RHS with a general N-by-N matrix A using the LU factorization

with complete pivoting computed by SGETC2.

ARGUMENTS

N (input) INTEGER

The order of the matrix A.

A (input) REAL array, dimension (LDA,N)

On entry, the LU part of the factorization of the

n-by-n matrix A computed by SGETC2: A = P * L * U * Q

LDA (input) INTEGER

The leading dimension of the array A. LDA >=

max(1, N).

RHS (input/output) REAL array, dimension (N).

On entry, the right hand side vector b. On exit,

the solution vector X.

IPIV (iput) INTEGER array, dimension (N).

The pivot indices; for 1 <= i <= N, row i of the

matrix has been interchanged with row IPIV(i).

JPIV (iput) INTEGER array, dimension (N).

The pivot indices; for 1 <= j <= N, column j of

the matrix has been interchanged with column JPIV(j).

SCALE (output) REAL

On exit, SCALE contains the scale factor. SCALE

is chosen 0 <= SCALE <= 1 to prevent owerflow in the solution.

FURTHER DETAILS

Based on contributions by

Bo Kagstrom and Peter Poromaa, Department of Computing

Science,
Umea University, S-901 87 Umea, Sweden.

LAPACK version 3.0 15 June 2000

SGESC2(3)